During a barium enema exam, air may be pumped into the colon. The air expands the colon and improves the quality of images. This is called an air-contrast (double-contrast) barium enema. Before a barium enema, your doctor will instruct you to completely empty your colon.
Best Answer: First one is the Upper Oesophageal Sphincter, which allows entry of a food bolus into the oesophagus. Then the Lower Oesophageal Sphincter (also known as cardia, or cardiac sphincter), found at the entrance to the stomach. This stops reflux of food back up the oesophagus. Next is the pyloric sphincter, which allows stomach contents into the duodenum (small intestine) for further digestion. Then the ilio-caecal valve, which isn't a sphincter, but mediates movement of small intestine contents into the large intestine (caecum). There are two sphincters around the anus, the external sphincter and the internal sphincter.
Sphincter â A circular band of muscle that surrounds and encloses an opening to the body or to one of its hollow organs. Damage to the sphincter surrounding the anus can cause fecal incontinence. Stools â Undigested food and other waste that is eliminated through the anus.